* {
            margin: 0;
            padding: 0;
            text-decoration: none;
        }
        body {
           /* margin: 100px; */
        /* height: 100px; */
        display: flex;
        align-items: center;
        justify-content: center;
        
            padding: 20px;
        }
        #container {
            position: relative;
            width: 900px;
            height: 400px;
            border: 3px solid #333;
            overflow: hidden;
        }
        #list {
            position: absolute;
            z-index: 1;
            width: 5400px;
            height: 400px;
        }
        #list img {
            float: left;
            width: 900px;
            height: 400px;
        }
        #buttons {
			
			position: relative;
			margin: auto;
			z-index: 2;
			height: 10px;
			width: 150px;
            /* position: absolute;
            left: 250px;
            bottom: 20px;
            z-index: 2;
            height: 10px;
            width: 150px; */
        }
        #buttons span {
            float: left;
            margin-right: 5px;
            width: 20px;
            height: 5px;
            border: 1px solid #fff;
            border-radius: 2px;
            background: #333;
            cursor: pointer;
        }
        #buttons .on {
            background: orangered;
        }
        .arrow {
            position: absolute;
            top: 180px;
            z-index: 2;
            display: none;
            width: 40px;
            height: 40px;
            font-size: 36px;
            font-weight: bold;
            line-height: 39px;
            text-align: center;
            color: #fff;
            background-color: RGBA(0, 0, 0, .3);
            cursor: pointer;
        }
        .arrow:hover {
            background-color: RGBA(0, 0, 0, .7);
        }
        #container:hover .arrow {
            display: block;
        }
        #prev {
            left: 20px;
        }
        #next {
            right: 20px;
        }